Re: [PATCH v10 05/13] kbuild: remove MODULE_LICENSE/AUTHOR/DESCRIPTION in non-modules

On Wed, Dec 7, 2022 at 2:04 PM Luis Chamberlain [off-list ref] wrote:

On Tue, Dec 06, 2022 at 10:02:30PM +0100, Arnd Bergmann wrote:

quoted

On Tue, Dec 6, 2022, at 21:03, Nick Alcock wrote:

quoted

On 6 Dec 2022, Geert Uytterhoeven uttered the following:
Only MODULE_LICENSE invokes MODULE_FILE and thus ends up introducing a
KBUILD_MODOBJS entry that triggers things going wrong iff not a module:
so only it needs to go out (or be replaced with a variant that doesn't
invoke MODULE_FILE, if you want to keep the license in too --

That sounds like a better alternative

quoted

but if the thing is no longer a standalone entity at all I'm not sure
what meaning it could possibly have).

As far as I can tell, the general trend is to make more things modules,
so there is a good chance that these come back eventually. If the
information in the MODULE_LICENSE field isn't wrong, I would just
leave it in there.

Tooling today uses it though to make a deterministic call on if something
*can* be a module. In particular after commit 8b41fc4454e ("kbuild: create
modules.builtin without Makefile.modbuiltin or tristate.conf") we rely on
the module license tag to generate the modules.builtin file. This in
turn is used to allow modprobe to *not* fail when trying to load a module
which is built-in.

If we have a bool driver 'foo.ko' in modules.builtin,
'modprobe foo' will not fail where you expect it will fail.

Is it so important to make this strict?

I do not think so.


What is a point for a user to realize
"Oh, I did not know foo cannot be compiled as a module"


Re-read the commit description of
bc081dd6e9f622c73334dc465359168543ccaabf

The motivation of module.builtin is to know the functionality 'foo'
is available (via built-in or module, whatever).

In this sense, having always-builtin entries in module.builtin is OK.


I do not see any sense in the tooling mess in this patch set.

So we can't just disable the tag for when the code is built-in as *want*
to carry it when modules are built-in, that is the point, to help
userspace with this determination.

I don't think we want to revert 8b41fc4454e as it means we'd force Kbuild to
traverse the source tree twice.

I do not want to revert it.

and I do not want this series in the mainline.

Geert's point was not keeping MODULE_LICENSE() but instead the other
MODULE_*() crap for things which are not modules in case in the future
code becomes a module...

But I don't see the point in keeping things around just in case, if we
want to keep things simple. Just use the SPDX license tag for the license.

  Luis

--
Best Regards
Masahiro Yamada